Drive arrangement having at least one electric motor and a coupling arrangement positioned on both sides of a transmission arrangement

Abstract

The invention relates to a propulsion assembly comprising a propulsion system, at least one electric motor (44) positioned in a first external zone (ZE1), a transmission system (46) and a coupling device which includes: - a first coupling shaft (68) coupled to an output (60) of the electric motor (44), passing through the transmission system (46) and having a first end (68.1) projecting into a second external zone (ZE2), - a second coupling shaft (70) coupled to an input (52) of the transmission system (46), passing through at least one wall of the transmission system (46) and having a first end (70.1) projecting into the second external zone (ZE2), - a coupling system (72) configured to rotationally couple the first ends (68.1, 70.1) of the first and second coupling shafts (68, 70), positioned in the second external zone (ZE2).The invention also relates to an aircraft comprising at least one such propulsion system.

Description

[0001] The present application relates to a propulsion assembly comprising at least one electric motor and a coupling system positioned on either side of a transmission system as well as to an aircraft comprising at least one such propulsion assembly. According to an embodiment visible on the figure 1 , an aircraft 10 comprises a fuselage 12, at least one wing 14 connected to the fuselage 12 as well as propulsion assemblies 16 connected to the wing 14 and arranged on either side of the fuselage 12. As illustrated in the figures 2 And 3 , each propulsion assembly 16 comprises a propeller 18 which has an axis of rotation A18.

[0002] For the remainder of the description, a longitudinal direction is parallel to the axis of rotation A18 of the propeller 18. The concepts “front” and “rear” refer to the direction of air flow relative to the aircraft in flight, the air flowing in the longitudinal direction, from front to rear.

[0003] An electric propulsion assembly comprises several electric motors 20 as well as a transmission system 22, such as a gearbox for example, configured to couple the electric motors 20 to the propeller 18.

[0004] As illustrated in the figure 3 , the transmission system 22 comprises a first housing 24 which has, in the longitudinal direction, a front wall F24 oriented towards the propeller 18 and a rear wall F24' on which the electric motors 20 are fixed as well as at least one kinematic chain 26 positioned in the first housing 24 which has at least one input 28 for each electric motor 20 and an output 30, in the form of an output shaft, passing through the front wall F24 to be coupled to the propeller 18.

[0005] Each electric motor 20 has a second housing 32 which comprises a bearing face F32, fixed against the rear wall F24' of the first housing 24, as well as an output shaft 34, projecting relative to the bearing face F32, passing through the rear wall F24' of the first housing 24. This output shaft 34 is coupled with one of the inputs 28 of the kinematic chain 26 of the transmission system 22 by a coupling system 36 positioned in the first housing 24 of the transmission system 22.

[0006] According to one embodiment, each coupling system 36 comprises a freewheel configured to occupy a coupled state in which the output shaft 34 of the corresponding electric motor 20 is coupled in rotation and transmits a rotational movement to the kinematic chain 26 of the transmission system 22 as well as an uncoupled state, in the event of an incident for example, in which the output shaft 34 of the corresponding electric motor 20 is no longer coupled to the kinematic chain 26 of the transmission system 22 and no longer transmits a rotational movement to it.

[0007] In this way, if an electric motor 20 no longer operates and its output shaft 34 is blocked in rotation, the coupling system 36 makes it possible to isolate it from the kinematic chain 26 which remains operational and transmits the rotational movements of the other electric motors 20 to the propeller 18.

[0008] The coupling systems 36 require more frequent maintenance operations than the other elements of the transmission system 22. For each of these, the transmission system 22 must be removed, which involves dismantling the electric motors 20, and its housing 24 must be opened in order to access the coupling systems 36. These different steps are relatively long, tedious and expensive.

[0009] Documents WO 2022 / 171945 A1, US 2023 / 017954 A1 and US 2023 / 021085 A1 describe propulsion assemblies according to the prior art.

[0010] The present invention aims to remedy all or part of the drawbacks of the prior art.

[0011] To this end, the invention relates to a propulsion assembly comprising a propulsion system, at least one electric motor and a transmission system coupled to the propulsion system, the transmission system comprising first and second transverse walls which delimit an inner zone located between the first and second transverse walls, a first outer zone separated from the inner zone by the first transverse wall and a second outer zone separated from the inner zone by the second transverse wall, the electric motor being connected to the first transverse wall and positioned in the first outer zone, said electric motor having an output coupled by a coupling device to an input of the transmission system positioned in the inner zone.

[0012] According to the invention, the coupling device comprises: a first coupling shaft coupled to the output of the electric motor, passing through the transmission system and having a first end projecting into the second outer zone, a second coupling shaft coupled to the input of the transmission system, passing through at least the second transverse wall and having a first end projecting into the second outer zone, a coupling system configured to rotationally couple the first ends of the first and second coupling shafts, positioned in the second outer zone.

[0013] According to the invention, the coupling system is positioned outside the transmission system. Consequently, it is no longer necessary to remove the transmission system and disassemble it to carry out maintenance on the coupling system, which increases the time between two maintenance operations on the transmission system. Arranging the electric motor and its associated coupling system on either side of the transmission system allows for a more compact assembly.

[0014] According to another feature, the second coupling shaft is hollow and configured to accommodate the first coupling shaft.

[0015] According to another characteristic, the first and second coupling shafts are coaxial.

[0016] According to another feature, the coupling system is positioned inside the second coupling shaft.

[0017] According to another characteristic, the coupling device comprises a plug configured to close the first end of the second coupling shaft, connected by a removable connection to the second coupling shaft.

[0018] According to a first embodiment, the electric motor comprises an output shaft passing through the transmission system, the output shaft and the first coupling shaft of the coupling device forming a single shaft.

[0019] According to a second embodiment, the electric motor comprises an output shaft positioned in the first outer zone. In addition, the first coupling shaft of the coupling device and the output shaft of the electric motor are two separate shafts, the first coupling shaft having a second end positioned in the first outer zone and coupled to the output shaft of the electric motor.

[0020] According to another characteristic, the second coupling shaft comprises a second end which cooperates with the first transverse wall. In addition, the propulsion assembly comprises a pivoting connection comprising a first rotational guide interposed between a section of the second coupling shaft and the second transverse wall as well as a second rotational guide interposed between the second end of the second coupling shaft and the first transverse wall.

[0021] According to another feature, the propulsion system is positioned in the second outer zone.

[0022] According to another feature, the coupling system is disengageable and configured to occupy a coupled state in which the output of the electric motor is rotationally coupled and transmits rotational movement to the input of the transmission system as well as an uncoupled state in which the output of the electric motor is no longer coupled to the input of the transmission system and no longer transmits rotational movement thereto.

[0023] According to another feature, the coupling system is configured to transition from the coupled state to the uncoupled state as soon as a torque transmitted via the coupling system exceeds a given threshold or is no longer within a given range.

[0024] According to another characteristic, the coupling system comprises a freewheel configured to occupy a rotationally coupled state in which the first coupling shaft is rotationally coupled and transmits a rotational movement to the second coupling shaft as well as an uncoupled state in which the first coupling shaft is no longer rotationally coupled to the second coupling shaft and no longer transmits a rotational movement thereto.

[0025] The invention also relates to an aircraft comprising at least one propulsion unit according to one of the preceding characteristics.

[0026] Other characteristics and advantages will emerge from the description of the invention which follows, a description given by way of example only, with reference to the appended drawings, among which: There figure 1 is a side view of an aircraft, The figure 2 is a schematic side view of an electric propulsion assembly illustrating an embodiment of the prior art, The figure 3 is a schematic section of a transmission system and electric motors of a propulsion assembly illustrating an embodiment of the prior art, The figure 4 is a schematic section of a part of a propulsion assembly illustrating an embodiment of the invention, The figure 5 is a sectional view of a portion of a transmission system, an electric motor, and a coupling system illustrating one embodiment of the invention.

[0027] According to an embodiment visible on the figure 4 , an electric type propulsion assembly 40 comprises a propeller 42 which has an axis of rotation A42, several electric motors 44 as well as a transmission system 46, such as a gearbox for example, configured to couple the electric motors 44 to the propeller 42.

[0028] According to one application, an aircraft comprises at least one such propulsion assembly 40. Of course, the invention is not limited to this application. Whatever the application, the electric type propulsion assembly 40 comprises a propulsion system, such as a propeller for example, several electric motors 44 as well as a transmission system 46 configured to couple the electric motors 44 to the propulsion system.

[0029] According to a configuration visible on the figure 4 , the transmission system 46 comprises a first housing 48 which has, in the longitudinal direction, a front wall F48 oriented towards the propulsion system and a rear wall F48', on which the electric motors 44 are fixed, as well as at least one kinematic chain 50 positioned in the first housing 48 which has at least one input 52 for each electric motor 44 and an output 54, in the form of an output shaft, passing through the front wall F48 to be coupled to the propulsion system. According to a configuration visible on the figure 4 , the input 52 of the transmission system 46 is a pinion. Of course, the invention is not limited to this embodiment. Thus, the input 52 of the transmission system 46 could be a hollow shaft or any other element allowing coupling and the transmission of a rotational movement.

[0030] Each electric motor 44 comprises a second housing 56 which has a first face 56.1 oriented towards the transmission system 46 as well as a second face 56.2 opposite the first face 56.1 and the transmission system 46. The propulsion assembly 40 comprises, for each electric motor 44, connecting elements 58 making it possible to fix the electric motor 44 to the first housing 48 of the transmission system 46. By way of example, the connecting elements 58 are screws, which pass through tabs secured to the second housing 56 of the electric motor 44, each screwing into a tapped hole secured to the first housing 48 of the transmission system 46. Of course, the invention is not limited to this embodiment for the connecting elements 58.

[0031] According to one arrangement, at least one electric motor 44 is positioned against the rear wall F48' of the first housing 48 of the transmission system 46 and connected to the rear wall F48' by the connecting elements 58.

[0032] According to another arrangement, at least one electric motor 44 is positioned against the front wall F48 of the first housing 48 of the transmission system 46 and connected to the front wall F48 by the connecting elements 58.

[0033] Regardless of the arrangement, the transmission system (more particularly its first housing 48) comprises a first transverse wall PT1 among the front and rear walls F48, F48' as well as a second transverse wall PT2, different from the first transverse wall PT1, among the front and rear walls F48, F48'. The first and second transverse walls PT1, PT2 delimit an inner zone ZI located between the first and second transverse walls PT1, PT2, a first outer zone ZE1 separated from the inner zone ZI by the first transverse wall PT1 as well as a second outer zone ZE2 separated from the inner zone ZI by the second transverse wall PT2. At least one electric motor 44 is connected to the first transverse wall PT1 and positioned in the first outer zone ZE1, said electric motor 44 having an output 60 coupled to an input 52 of the transmission system 46 positioned in the inner zone ZI.

[0034] Each electric motor 44 comprises an output 60, such as an output shaft 62 for example connected to the second housing 56 by a pivoting connection 64, which has a pivot axis A62.

[0035] According to one arrangement, the pivot axis A62 of the output shaft 62 is substantially parallel to the longitudinal direction. The first and second faces 56.1, 56.2 are substantially perpendicular to the pivot axis A62 and offset from each other in the longitudinal direction.

[0036] According to a configuration visible on the figure 4 , the output shaft 62 extends from the first face 56.1, passes through the transmission system 46, in particular the front and rear walls F48, F48' of the first housing 48, and has a free end 62.1 projecting relative to the front wall F48, offset forwards relative to said front wall F48.

[0037] According to another configuration visible on the figure 5 , the output shaft 62 is hollow and offset rearwardly relative to the first face 56.1 of the second housing 56 and the rear wall F48' of the first housing 48.

[0038] Of course, the output 60 of the electric motor 44 is not limited to these configurations. Thus, the output 60 of the electric motor 44 could be a pinion or any other element allowing coupling and transmission of a rotational movement.

[0039] The propulsion assembly 40 comprises at least one coupling device 66 connecting the output 60 of one of the electric motors 44 located in the first external zone ZE1 and the input 52 of the transmission system 46, configured to transmit a rotational movement between the output 60 and the input 52.

[0040] This coupling device 66 comprises: a first coupling shaft 68 coupled to the output 60 of the electric motor 44, passing through the first housing 48 and having a first end 68.1 projecting into the second outer zone ZE2, a second coupling shaft 70 coupled to the input 52 of the transmission system 46, passing through at least the second transverse wall PT2 of the first housing 48 and having a first end 70.1 projecting into the second outer zone ZE2, a coupling system 72 configured to rotationally couple the first ends 68.1, 70.1 of the first and second coupling shafts 68 70, positioned in the second outer zone ZE2.

[0041] According to one configuration, the propulsion assembly 40 comprises a coupling device 66 for each electric motor 44 whether it is positioned in the first exterior zone ZE1 or in the second exterior zone ZE2.

[0042] The coupling system 72 is disengageable and configured to occupy a coupled state in which the output 60 of the electric motor 44 is rotationally coupled and transmits a rotational movement to the input 52 of the transmission system 46 as well as an uncoupled state, in the event of an incident for example, in which the output 60 of the electric motor 44 is no longer coupled to the input 52 of the transmission system 46 and no longer transmits rotational movement to it. The coupling system 72 passes from the coupled state to the uncoupled state, in the event of an incident for example, as soon as a torque transmitted via the coupling system 72 exceeds a given threshold or is no longer within a given range.

[0043] In this way, if the electric motor 44 coupled to the coupling system 72 no longer operates and its output shaft 62 is blocked in rotation for example, the coupling system 72 makes it possible to isolate it from the transmission system 46 which remains operational and transmits the rotational movements of the other electric motors to the propulsion system.

[0044] According to one embodiment, the coupling system 72 comprises a freewheel 72.1 configured to occupy a rotationally coupled state in which the first coupling shaft 68 is rotationally coupled and transmits a rotational movement to the second coupling shaft 70 as well as a decoupled state, in the event of an incident for example, in which the first coupling shaft 68 is no longer rotationally coupled to the second coupling shaft 70 and no longer transmits a rotational movement to it.

[0045] According to one configuration, the coupling system 72 comprises first and second rotation guides 72.2, 72.3 positioned on either side of the freewheel 72.1. The latter comprises a ring having an inner surface which cooperates with the first coupling shaft 68 as well as an outer surface which cooperates with the second coupling shaft 70, at least one of the surfaces among the inner and outer surfaces being coupled by friction with the first or second coupling shaft 68, 70.

[0046] The freewheel 72.1 being located outside the first housing 48 of the transmission system 46, any dust generated by the friction coupling of the freewheel 72.1 does not pollute the interior of the transmission system 46, thus limiting the risks of premature degradation of the components of the transmission system 46.

[0047] To obtain a more compact assembly, for at least one electric motor 44, the second coupling shaft 70 is hollow and configured to house the first coupling shaft 68. According to one arrangement, the first and second coupling shafts 68, 70 are coaxial.

[0048] According to one arrangement, the coupling system 72 is positioned inside the second coupling shaft 70, between first ends 68.1, 70.1 of the first and second coupling shafts 68, 70, which makes it possible to protect it.

[0049] In addition, the coupling device 66 comprises a plug 74 configured to close the first end 70.1 of the second coupling shaft 70, connected by a removable connection to the second coupling shaft 70. This embodiment makes it possible to reinforce the protection of the coupling system 72.

[0050] According to a first embodiment visible on the figure 4 , the output shaft 62 of the electric motor 44 and the first coupling shaft 68 of the coupling device 66 form a single shaft. This shaft can be hollow or solid.

[0051] According to a second embodiment visible on the figure 5, the output shaft 62 of the electric motor 44 is positioned in the first outer zone ZE1 and distinct from the first coupling shaft 68 of the coupling device 66. According to this embodiment, the first coupling shaft 68 comprises a second end 68.2 positioned in the first outer zone ZE1 and coupled to the output shaft 62 of the electric motor 44. According to one embodiment, the output shaft 62 of the electric motor 44 is hollow and configured to receive the second end 68.2 of the first coupling shaft 68. For example, the second end 68.2 and the output shaft 62 are splined. Other solutions are conceivable for coupling the output shaft 62 of the electric motor 44 and the first coupling shaft 68 of the coupling device 66.

[0052] According to one embodiment, the coupling device 66 comprises a pinion 76 secured to the second coupling shaft 70 and fixed relative to the latter, which cooperates with a pinion or a crown of the input 52 of the transmission system 46.

[0053] According to one arrangement, the propulsion assembly 40 comprises a pivoting connection 78 connecting the second coupling shaft 70 and the first housing 48 of the transmission system 46. According to one embodiment, the second coupling shaft 70 comprises a second end 70.2 which cooperates with the first transverse wall PT1. In addition, the pivoting connection 78 comprises a first rotational guide 78.1, such as a bearing for example, interposed between a section 70.3 of the second coupling shaft 70 and the second transverse wall PT2 as well as a second rotational guide 78.2, such as a bearing for example, interposed between the second end 70.2 of the second coupling shaft 70 and the first transverse wall PT1.

[0054] According to a first configuration, the electric motors 44 are all positioned against the rear wall F48' of the transmission system 46 and the coupling system 72 of each of them is positioned in front of the front wall F48 of the transmission system 46, in the second external zone ZE2 in which the propulsion system is positioned.

[0055] According to another configuration, at least one electric motor 44 is positioned against the front wall F48 of the transmission system 46 and the coupling system 72 associated with it is positioned at the rear of the rear wall F48'.

[0056] Regardless of the embodiment, the coupling system 72 is positioned outside the first housing 48 of the transmission system 46. Consequently, it is no longer necessary to remove the transmission system 46 and disassemble it to carry out a maintenance operation on the coupling system 72, which makes it possible to increase the time between two maintenance operations on the transmission system 46. Arranging the electric motor 44 and the coupling system 72 associated with it on either side of the transmission system 46 makes it possible to obtain a more compact assembly. Furthermore, when the coupling system 72 is positioned at the front of the transmission system, it is more accessible, which facilitates maintenance operations.

Claims

1. Propulsion unit comprising a propulsion system, at least one electric motor (44), a coupling device (66), in addition to a transmission system (46) which is coupled to the propulsion system, the transmission system (46) comprising first and second transverse walls (PT1) which delimit an internal zone (ZI) which is located between the first and second transverse walls (PT1, PT2), a first external zone (ZE1) which is separated from the internal zone (ZI) by the first transverse wall (PT1), in addition to a second external zone (ZE2) which is separated from the internal zone (ZI) by the second transverse wall (PT2), the electric motor (44) being connected to the first transverse wall (PT1) and being positioned in the first external zone (ZE1), and said electric motor (44) having an output (60) which is coupled by the coupling device (66) to an input (52) of the transmission system (46) which is positioned in the internal zone (ZI); characterized in that the coupling device (66) comprises: - a first coupling shaft (68) which is coupled to the output (60) of the electric motor (44), passing through the transmission system (46) and having a first end (68.1) protruding into the second external zone (ZE2), - a second coupling shaft (70) which is coupled to the input (52) of the transmission system (46), passing through at least the second transverse wall (PT2) and having a first end (70.1) protruding into the second external zone (ZE2), - a coupling system (72) which is configured to couple the first ends (68.1, 70.1) of the first and second coupling shafts (68, 70) in terms of rotation and which is positioned in the second external zone (ZE2).

2. Propulsion unit according to the preceding claim, characterized in that the second coupling shaft (70) is hollow and is configured to house the first coupling shaft (68).

3. Propulsion unit according to the preceding claim, characterized in that the first and second coupling shafts (68, 70) are coaxial.

4. Propulsion unit according to either of Claims 2 and 3, characterized in that the coupling system (72) is positioned inside the second coupling shaft (70).

5. Propulsion unit according to the preceding claim, characterized in that the coupling device (66) comprises a plug (74) which is configured to seal the first end (70.1) of the second coupling shaft (70) and which is connected by a releasable connection to the second coupling shaft (70).

6. Propulsion unit according to one of the preceding claims, characterized in that the electric motor (44) comprises an output shaft (62) passing through the transmission system (46) and in that the output shaft (62) and the first coupling shaft (68) of the coupling device (66) form one and the same shaft.

7. Propulsion unit according to one of Claims 1 to 5, characterized in that the electric motor (44) comprises an output shaft (62) which is positioned in the first external zone (ZE1) and in that the first coupling shaft (68) of the coupling device (66) and the output shaft (62) of the electric motor (44) are two separate shafts, the first coupling shaft (68) comprising a second end (68.2) which is positioned in the first external zone (ZE1) and which is coupled to the output shaft (62) of the electric motor (44).

8. Propulsion unit according to one of the preceding claims, characterized in that the second coupling shaft (70) comprises a second end (70.2) which cooperates with the first transverse wall (PT1) and in that the propulsion unit (40) comprises a pivoting connection (78) comprising a first rotating guide (78.1) which is interposed between a portion (70.3) of the second coupling shaft (70) and the second transverse wall (PT2), in addition to a second rotating guide (78.2) which is interposed between the second end (70.2) of the second coupling shaft (70) and the first transverse wall (PT1).

9. Propulsion unit according to one of the preceding claims, characterized in that the propulsion system is positioned in the second external zone (ZE2).

10. Propulsion unit according to one of the preceding claims, characterized in that the coupling system (72) is able to be disengaged and is configured to adopt a coupled state in which the output (60) of the electric motor (44) is coupled in terms of rotation and transmits a rotational movement to the input (52) of the transmission system (46), in addition to an uncoupled state in which the output (60) of the electric motor (44) is no longer coupled to the input (52) of the transmission system (46) and no longer transmits any rotational movement thereto.

11. Propulsion unit according to one of the preceding claims, characterized in that the coupling system (72) comprises a freewheel (72.1) which is configured to adopt a state which is coupled in terms of rotation and in which the first coupling shaft (68) is coupled in terms of rotation and transmits a rotational movement to the second coupling shaft (70), in addition to an uncoupled state in which the first coupling shaft (68) is no longer coupled in terms of rotation to the second coupling shaft (70) and no longer transmits any rotational movement thereto.

12. Aircraft comprising at least one propulsion unit according to one of the preceding claims.

Images